The broad, long-term objective of this proposal is to reduce the incidence of motor vehicle crashes (MVCs) caused by inexperienced teen drivers, as MVCs are the leading cause of death for this age group. We will achieve this goal by examining the long-term effectiveness of the TeenDrivingPlan (TDP) on the sustainability of safe driving behaviors. Specific Aim 1: Evaluate the long-term impact of TDP on teens' development of safe driving behaviors by assessing the effect of TDP on teens' entry into the intermediate period of GDL (time to licensure, number of attempts to pass the test) and risky driving behavior during the post-license period indexed by receipt of traffic citations, risky driving behaviors, and motor vehicle crash involvement. Specific Aim 2: Evaluate and refine TDP's program theory. Aim 2 analyses will inform theory by explicating the key individual difference variables and parent-teen interpersonal processes that promote sustainable safe driving behavior, the extent to which these processes are malleable via a web-based behavioral intervention, and if the benefit of inculcating safe driving behaviors and increasing parental engagement on driving issues during the learner stage is sustainable into the post license driving period. Proposed analyses will contribute to theory relating to the optimal forms of supervision of teen drivers by parents and inform revisions to the TDP program, thereby setting the stage for a future large-scale evaluation of an optimized version of TDP.